GenerateBlocks Query Loop – Random post that stays fixed for 24 hours

Hi,

This requires custom PHP since the Query Loop’sorderby=rand will always re-randomize on each page load.

The solution uses a transient to cache the randomly selected post ID until midnight, so it stays fixed for the day:

add_filter( 'generateblocks_query_loop_args', function( $query_args, $attributes ) {
    
    $classes = $attributes['className'] ?? '';
    
    if ( strpos( $classes, 'post-of-the-day' ) === false ) {
        return $query_args;
    }
    
    $transient_key = 'post_of_the_day_id';
    $post_id = get_transient( $transient_key );
    
    if ( false === $post_id ) {
        $random_post = get_posts( array(
            'post_type'      => $query_args['post_type'] ?? 'post',
            'posts_per_page' => 1,
            'orderby'        => 'rand',
            'fields'         => 'ids',
        ) );
        
        if ( ! empty( $random_post ) ) {
            $post_id = $random_post[0];
            
            // Cache until midnight (based on Settings → General → Timezone)
            $now = current_time( 'timestamp' );
            $midnight = strtotime( 'tomorrow midnight', $now );
            set_transient( $transient_key, $post_id, $midnight - $now );
        }
    }
    
    if ( $post_id ) {
        $query_args['post__in'] = array( $post_id );
        $query_args['orderby'] = 'post__in';
    }
    
    return $query_args;
}, 99, 2 );

Setup:

1. Add the code to your child theme’s functions.php or a code snippets plugin
2. On your Query Loop block, add the CSS class post-of-the-day (Settings -> Additional CSS Class(es))
3. Set Posts Per Page to 1
4. Remove any orderby=rand setting from the Query Loop itself

The random selection happens once per day at midnight, and that post is then shown to all visitors until the next midnight. Note that “midnight” is based on the timezone set in Settings -> General -> Timezone.

Note on caching: If you’re using page caching (LiteSpeed, WP Rocket, Cloudflare, etc.), the cached page may continue showing the old post even after midnight until the cache clears. You may need to either:

• Set your page cache TTL to expire around midnight
• Exclude this page from page caching
• Set up a scheduled cache purge at midnight

The transient itself will work correctly — it’s just that visitors may see a cached version of the page until it refreshes.

Hi,

You just need to modify the get_posts() arguments inside the filter. The caching behavior stays the same.

Here are examples for each scenario:

Filter by category:

$random_post = get_posts( array(
    'post_type'      => 'post',
    'posts_per_page' => 1,
    'orderby'        => 'rand',
    'category_name'  => 'daily-prayer', // Use the category slug
    'fields'         => 'ids',
) );

Filter by tag:

$random_post = get_posts( array(
    'post_type'      => 'post',
    'posts_per_page' => 1,
    'orderby'        => 'rand',
    'tag'            => 'featured', // Use the tag slug
    'fields'         => 'ids',
) );

Filter by specific post IDs:

$allowed_posts = array( 123, 456, 789 ); // Your chosen post IDs

$random_post = get_posts( array(
    'post_type'      => 'post',
    'posts_per_page' => 1,
    'orderby'        => 'rand',
    'post__in'       => $allowed_posts,
    'fields'         => 'ids',
) );

Combine multiple filters:

$random_post = get_posts( array(
    'post_type'      => 'post',
    'posts_per_page' => 1,
    'orderby'        => 'rand',
    'category_name'  => 'daily-prayer',
    'tag'            => 'featured',
    'fields'         => 'ids',
) );

The transient caching logic remains unchanged — it will just select from your filtered pool instead of all posts.

You are welcome!